1. Field of the Invention
The present invention relates to a cruise control for an automobile, especially to a system uses a video camera to detect a vehicle driving ahead so that a system can keep a constant distance to the vehicle as well as a constant speed.
2. Description of the Prior Art
A conventional cruise control system is shown in Japanese Patent Laid Open 62-153531 (1987). When many vehicles are running at relatively high speed in a highway using cruise controls, distances between vehicles often become closer. Japanese Patent Laid Open 64-66712 (1989) shows a system has a video camera mounted on a vehicle. A video camera takes pictures of the scenes ahead of the vehicle. The pictures are processed to detect the lanes and a vehicle driving in the lane ahead of the vehicle. A system decreases the speed of the vehicle when a distance becomes smaller than a predetermined distance to keep safety.
This conventional system controls a speed set by a driver, however, it is better to drive at a speed matching with a flow of vehicles in a highway. This reduces driver's fatigue and dangerous situations caused by deference of the speeds.